- "Okay. Here we go. Ram the wall. Going to ram it with my car. Just smash through it. Take out the power. Save my friends. Here we go. Alright. Just ram it and destroy my beautiful car that my parents bought on my birthday, but I'm going to save my friends. Here we go. Ram the wall."
- ―Mason to himself[src]
New kids Garrett, Violet, and Mason get off the school bus. Garrett complains about how he's not watching another movie on a Friday night. Mason points out that they're freshmen. They're not going to be hitting clubs until 4am. Violet settles on a movie at Mason's at 9. Liam comes running up as Garrett and Violet leave. Mason asks him why he wasn't on the bus, and he says he ran to school from home, all 3 miles. Mason points out that this must mean his leg is okay, but then he asks about the wound on Liam's arm, where Scott bit him. Liam starts breathing heavily and looking ill. Liam tells Mason that he has to get to class and hurries away from Scott. After class, Kira walks down the steps as Liam and Mason leave class. Her hair flutters in nonexistent wind. Halfway down the steps, she falters and falls on her face. Liam rushes over to see if she's okay. Later that night, Mason texts Liam asking where he is. Liam replys saying that he is going to a party. Mason then invites everyone and everyone arrives at Lydia's house. During the party, Mason looks for Liam and goes upstairs and Lydia chases after him. Mason looks for Liam upstairs. Lydia follows him into a very white room and asks what he's doing up there. He says he's looking for Liam, and Lydia claims that missing freshman are low on her priority list. Mason points out that he can't be so low if she knows he's a freshman. Lydia grabs two wine glasses and tries to hurry Mason out, but she drops the glasses with red wine. Lydia drops to her knees and starts trying to clean the carpet with her shirt. Mason assures her that the wine will come out. He asks her if the carpet's valuable. "No. That's the problem. Nothing in here is valuable." She starts to cry and explains to him that they put the house on the market and everything has to be in perfect condition to sell for enough. Mason offers to get some club soda and salt and assures her that it will come out. Mason gets up to leave, and when the door closes behind him. 
In the weight room at school, Mason is talking to Liam as he lifts free weights. Liam is obviously distracted as he keeps adding weight to a bench press machine, wondering why it still feels so light. Mason tells him that the “housing development” that Garrett supposedly lives in is literally “still in development” with no houses, therefore Garrett is obviously not telling them something. Liam adds more weight as Mason starts describing him as acting strange, running to school, disappearing at parties, and apparently on steroids. The line about steroids gets Liam’s attention, and Mason asks if he’s seriously going to lift the ridiculous amount of weight that he has on the machine now. Mason asks him if he’s okay, and he insists that he is, even though they’re going to play his old school, Devenford Prep, in the scrimmage that night. Later, Mason chases after Liam who has walked outside to where the players from Devenford Prep are getting off of the bus. Liam immediately approaches Brett, and tries to smooth things over, wishing him a good game, but Brett and his friends laugh and make a joke about “anger management”. The Devenford Prep players prepare for the game and Liam tells Mason that he thinks he can take Brett. Liam catches Mason checking Brett out as he changes shirts, and Mason eventually acquiesces that yes, he was, before saying “I think you could definitely take him... and then give him to me.” This dispels the tension and Liam laughs. 
Mason and Liam are running down a street in a wooded area. Mason is weirded out by the fact that they were friends with these killers. "They were using us for their cover. I mean professional killers were using us. How are you not freaking out about that?" Liam replies that he's freaking out about a lot and then starts running faster. He runs away from Mason, who has no chance at keeping up. When Mason finally catches up, he doesn't see Liam anywhere and doesn't notice the blood on the ground. Later, Coach Finstock tells Mason and Scott that Liam wasn't in class. He figures maybe he's sick like Coach seems to be. Mason says that Liam didn't look sick on their run, and they both are worried that Liam isn't responding to their texts. The bell rings, and Scott assures Mason that he'll find him. 
At school, Mason asks Liam if he's going to the bonfire, which is a Cyclones tradition, but Liam doesn't want to go. Mason insists that they're going to find Liam a nice girl that he can embarrass himself in front of and find him a lacrosse player. Liam thinks he sees a berserker in the hallway and tries to block it out. He eventually agrees to go to the bonfire just to get away. At the party, Mason watches skeptically as Liam puts more alcohol into his drink. Liam eyes him and then asks whether he's going to tell him to slow down. On the contrary, Mason was going to tell him to keep drinking so he'll get drunk enough to tell him the truth about what's really been going on. Mason says he isn't asking because he wants to know, he's asking because he wants to help. Liam looks over at Scott and Malia and then declares that he's going to get another drink. He drops his bottle on the ground and stumbles a little and claims he's getting drunk. Not long after, Scott brings Malia over to them both. Scott brings Malia a bottle of water, thinking she is really drunk somehow. He asks Mason how much Liam has had to drink. "Not enough to get him like this," Mason replies. Scott realizes that something is wrong and they need to get them out of there, but just as he says it he starts to feel the same effects. Mason asks him how much he drank. "Nothing. Not even a sip." He hears something in the thumping of the music and realizes that it's soundwaves that are making them ill. Scott tells Mason that he has to turn off the music. Mason doesn't understand why, but he nods when Scott tells him to keep his eye on Malia and Liam. Deputies grab Malia and Liam. Mason tries to stop them, but they declare that his friends are overly intoxicated. Mason offers to go with them, but the deputy shoves him down. Mason stares at the DJ and decides to follow through with Scott's plan. He finds where the audio equipment is plugged in. Mason pulls the power on the music. 
Liam and Mason are playing video games in Liam's room. Mason demands to know how Liam got so good. "Have you been practicing, or did you just suddenly get superhuman reflexes?" Liam quickly says he's been practicing. Mason gets up to leave, but Liam begs him to stay. Mason catches on that something is up, but when he asks if Liam is okay, Liam tells him he should leave. Later, Liam and Mason are in the weight room. Liam puts a lot of weight on the bench press and Mason offers to spot him. Liam is snide about it and refuses his help. He lifts the bar just to prove Mason wrong. Mason has enough of Liam's attitude and leaves. Later, Mason drops a new video game next to Liam. "I know something's going on. I know you don't want to talk about it. But you're still my best friend." Mason says that the last good friend he made was a professional killer, so he's running low on friend options. He says that Liam should talk when he's ready, but until then he's going to kick his ass in at least one of their video games. Liam picks one up. "Never played this one." At the lacrosse game, Mason and the rest of the crowd takes their seats for the game. 
Mason is at the school at a study group and is asked to search for Lydia. Mason checks the parking lot and confirms that Lydia's car is there. He offers to look around the school for her. Mason wanders around checking empty classrooms. He eventually finds Kira's jacket and Lydia's phone in the stairwell. He tries to turn on her phone and gets a photo of a berserker. A shadow falls over him, and he looks up to see a berserker in real life and knocks him out. Lydia reaches out and touches his face. He wakes up with a start. He starts describing the berserker to her, and she just nods. Their phones are gone, too. Mason asks what the berserker is going to do them, but Lydia doesn't know. "But it definitely doesn't want us to leave." "Lydia, why do you keep saying 'it'?" The berserker then growls, and they both turn to look down the hallway toward it. Mason asks what it is. "Not human," Lydia replies. Lydia and Mason are pressed side by side against a wall, hiding. Lydia doesn't hear the berserker so she wants to go. Mason tells her that there's only one way out from this side of the basement. She knows. Mason asks how she knows, and she sighs that she just does. Mason leans out to see if the berserker is blocking the exit, and he walks into view. Lydia finds a basket of bats. She picks one up. She takes the metal bat and marches toward the berserker. Mason suddenly comes running passed her, yelling, and takes a swing. The berserker backhands him, throwing him all the way down the hallway. Lydia takes her shots, and then she too gets smacked down the hall. The berserker starts coming for them. "Excuse me," the Sheriff says. "Catch." He throws something at the berserker, and it catches it. It's the claymore mine. Lydia and Mason take cover, and then the Sheriff blows the mine. The berserker explodes into dusk. Lydia tells him that the berserker wanted her to stay in Beacon Hills. "they were trying to kill someone." "Kill who?" Mason asks. Lydia's eyes well up. "Scott." 
Finding out about the Supernatural
Mason is looking into what attacked him at the end of last season. Liam isn't giving anything away though. They both go into class. After class, Liam distracts Mason from the endless barrage of questions by sending him after his soccer team crush. At somepoint, Mason and Liam arrange to work out later, but Liam doesn't show up. When he eventually shows up, he was prepared to tell him everything when he was interupted by a black wolf. The black wolf forces them back into the school before Liam finally wolfs out and scares the black wolf away while Mason watches with his mouth wide open. He responds with "Cool". 
Everyone meets at the school to talk. Stiles quips that now Tracy is the night terror since no one can find her. Scott starts to say that he knows they're all tired and miserable, except for Mason, who is looking at all of them with awe. He motions at Kira. "You're a kitsune. I don't even know what that is!" Stiles admonishes Liam because while they said he could tell Mason they didn't say he could invite him to the inner circle. Later, Mason and Liam find Brett on the lacrosse field at Liam's old school. Mason watches Brett play, shirtless, and gawks. "So he's a werewolf, too?" "Yep." "This just gets better and better." Meanwhile, Mason and Liam show Brett a picture of Tracy. "Cute. Never seen her." Liam asks if Satomi could have turned her without Brett knowing. Brett says that after the dead pool she's not really doing much recruiting. Mason asks if that's how it works, alphas just go around biting people. "Or you can be born like me and my sister. Satomi took us in after our family died in a fire." In the woods, Liam, Mason, and Brett search for the hole that Liam fell in. Mason falls into a hole but there's no necklace. Mason says that the hole doesn't look like a sink hole. There are handprints and dirt on the edges. They realize that someone was buried there. "Intense," Mason says. Liam searches the hole himself and agrees that the necklace isn't there. He doesn't think this is the same hole he fell in earlier. "Then who crawled out of this one?" Mason asks. 
Liam is accompanying Mason to a rave where he will serve as his wingman. Liam runs into his old friend who almost didn't let them into the club. The club called Sinema, a gay club. Mason seems to be interested in Lucas who shows off his supernatural strength, sending Liam into a protective mode. While Liam was distracted, Lucas leads Mason off. They start kissing and Lucas begins showing his spikes again. Liam is trying to fight off Lucas, when Scott and Kira show up a bit late to help the battle. The fight continues and ends Liam slamming Lucas to the ground. Kira goes to deliver an deathblow but she is stopped by Scott who looks at her very uncharacteristically. Before they could get Lucas out the Dread Doctors kill him. 
Kira is in the library trying to read the book. Mason appears next to her. "Not into sci-fi?" He thought they were supposed to finish reading it last night. Kira admits to him that she can barely read it and she doesn't know why. Mason sits next to her and asks if she speaks Japanese. "No. I'm also half-Korean and I don't speak Korean. And I'm pushing a C-average in English." Mason explains that he's been researching kitsunes. Outside, Mason and Brett are sitting on the bleachers talking about supernatural warning signs they can look for. Brett offers that being able to see in the dark and eyes that reflect the light are good clues. Brett asks Mason what the deal is between Hayden and Liam. Mason explains that in sixth grade Liam was getting into a figth with another kid. Hayden accidentally walked into the fight and got punched. She has a broken nose in her yearbook photo. But she hit Liam back, and he had a broken nose in his photo too.